Part IV: THE HUMAN
ANIMAL
Itis exciting to pick up an oyster shell as you walk along the beach and
to realizethatthis shell was once the home of asoft-bodiedanimal thatwas
capableofmakinga milky pearl toprotectitselfagainstanirritatinggrainof
sand. Itis mystifying to watch a fluffy yellow chick crackthroughthe shell
ofan egg. Itis fun, too, to examine the amazingly varied and sometimes
comical protozoathroughyour microscope. All life is fascinating and ever-
lastinglymiraculous.
But it is most thrillingofall to learn aboutyour own body and how
naturehas adaptedit to carryon all the necessary life functions, such as
digestion and respiration and thecirculation ofblood. Ofcourse, it isn't
possible for us to study the internalorgans of the humanbody. This we
leave to studentsof medicine. But we can achieve a good understandingof
ourown bodies by studying the animals whose organs most closely resemble
ours.
In the experimentsthatfollow, you will study theheartand lungsofa
cow and the kidneysofa lamb. Instructurethese organs are very similar to
the correspondinghuman organs, and they are identical in function. You
will learn why you have different typesofteeth and how it isthatyour tongue
can distinguish among various taste sensations. Those of you who want to
invest in someadditionalequipmentcan make a working model of thehuman
chest cavity. Whatbetterway tounderstandthe way your lungs work!
Also included among the following experiments are some activitiesthat
will show you the differences betweenhumanbeings andotheranimals. In the
process of seeing howhabitsare formed and how we learn by amethodcalled
"trial-and-error"you willhavea lot of fun.
The ability to learn new waysofdoing things and to form habits is one
ofthe primarydifferences betweenhumanbeings and otheranimals. You
will see for yourselfwhyman'sbrainmakes him superiorto all the other
animals.
Manyofthese experiments call forcompanions. They make lively games
forpartiesor for any slow rainyafternoon-allyou need are pencils andpaper!